Functional Surfaces As Initial Product Design Concept In
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21ST INTERNATIONAL CONFERENCE ON ENGINEERING DESIGN, ICED17 21-25 AUGUST 2017, THE UNIVERSITY OF BRITISH COLUMBIA, VANCOUVER, CANADA FUNCTIONAL SURFACES AS INITIAL PRODUCT DESIGN CONCEPT IN 3D-CAD-SYSTEMS Katzwinkel, Tim; Jacobs, Georg; Löwer, Manuel; Schmid, Alexander; Schmidt, Walter; Siebrecht, Justus RWTH Aachen, Germany Abstract Finding an initial shape design for innovative product concepts is one of the most challenging and most creative parts in product design processes. To support design engineers during that particular phase, knowledge based design automation tools can be used. This paper proposes an enhancement of existing design methodologies in terms of initial shape design of innovative product concepts.The presented approach consolidates PLM and parametric 3D CAD technologies into one integrated method. A concept of parametric working surfaces as an institutionalized feature embedding product lifecycle knowledge is described and briefly demonstrated with a software example. The approach intends to support the product designer with additional information from different company departments as well as giving the designer a tool to explicitly declare the design intent of its design concept in the very early phase of geometric shape definition. Keywords: Computer Aided Design (CAD), Design methods, Knowledge management, Virtual Engineering (VE), Product Lifecycle Management (PLM) Contact: Tim Katzwinkel RWTH Aachen Chair and Institute for Engineering Design Germany [email protected] Please cite this paper as: Surnames, Initials: Title of paper. In: Proceedings of the 21st International Conference on Engineering Design (ICED17), Vol. 6: Design Information and Knowledge, Vancouver, Canada, 21.-25.08.2017. 197 1 INTRODUCTION When creating innovative product concepts, there is a first design phase for every new development of mechatronic products. In this phase, the analytically and/or theoretically determined requirements, physical effects, solution principles and feature properties of a product concept have to be converted into a discrete first geometric form. In the context of this contribution, this phase is called "initial design". Figure 1 shows the integration of the initial design phase in the early phases of a generic product development process. In the field of system engineering, various existing solutions can be reused as templates or implemented as partial solutions to fulfil an overriding purpose. For example, partial functions can be realized by using purchased parts (e.g. automotive supplier) or standard components (e.g. machine elements). In contrast, in the case of an innovative part design from scratch no existing geometry can be referenced. Therefore, a first coarse shape of the part geometry has to be defined individually by the design engineer. Today's established design methods lack of strategies for the systematic and knowledge-based transformation of the theoretically developed product concepts (e.g. function structures, product structures) into a discrete first geometric shape in a standardized and tool based way (Tomiyama et al., 2009). In the past, a lot of efforts have been made in automation of design embodiment tasks in the field of requirement engineering, system engineering and knowledge-based engineering. The problem of shape finding within product design tasks has been addressed in the recent past, even though approaches concern descriptive information enhancement and recombination of existing geometric patterns (Hoisl and Shea, 2013). In respect to the capability of today’s 3D-CAD-Systems and their strong integration in product lifecycle management (PLM) environments, the automation of the initial design phase in product development processes seems a consequent enhancement of design automation approaches. Figure 1. Initial design phase in a generic product development process according to Pahl and Beitz (Pahl et al., 2015) Compared to heuristic approaches in initial design, the methodical anchoring of working surface definition within the PLM environment bears a high potential for a sustainable and continuous assistance of the product designer throughout the whole product development process. The novel approach to initial design shape synthesis proposed in this paper is a combination of knowledge based engineering and working surface modelling with a PLM based data integration. The working surface not only represents the initial product geometry but is enhanced with parametric information through the PLM-backbone (e.g. physical effect, fulfilled product function, calculation parameters). With a connection to PLM the interdependencies between shape design iterations and product characteristics in terms of solution quality, producability and economical aspects get computable. This is an important step to bring design automation into the described initial design phase. Modern product developments and innovative design concepts are often realized in a collaborative framework of different company departments (e.g. engineering, manufacturing, purchasing, sales, service) as well as multinational facility units. The challenging task of collaborative engineering throughout departments and facilities in the initial design phase can be enhanced by standardized and exchangeable design features as well. In addition, defining the initial product shape with respect to the known restrictions from all involved design domains has the potential to improve the efficiency of common design tasks by reducing the amount of necessary iterations to define the most feasible and economical product concept. 198 ICED17 2 STATE-OF-THE-ART In recent decades, the systematic development of products has been intensively researched. Various design methodologies and guidelines have been developed. Pahl and Beitz introduced a model that systematically links individual activities during a product planning and design process and maps them with additional consideration of a time component within a definite course of action (Pahl et al., 2015). This process consists of four main phases starting with the assignment of the overall task and ranging to the discrete solution, while the course allows unavoidable iterations in practical use and has been implemented into the well-known guideline VDI 2221 (VDI, 1993). As presented by Suh in his Axiomatic Design theory, the transformation of predefined requirements into feasible solutions in a methodological way leads to well-structured designs of technical systems (Suh, 2001). The function- behavior-state model (FBS) of Umeda et al. focusses on the different aspects of physical effects depending on the engineering viewpoint (Umeda et al., 1990). Besides the discussed approaches, a comprehensive overview of product development methodologies and the use of function concepts in particular are given by Tomiyama (Tomiyama et al., 2009). Due to the rising capacities of computer automation as well as the affordability of software tools and hardware components the research topic of design automation has been intensified lately. According to Rigger a lot of research effort has been made in task categorization and method selection as well as system architecture design and optimization (Rigger et al., 2016). According to Pahl the systematic approach to a product design concept involves first the selection of one or several physical effects that realize the desired functionality. In a following synthesis step the principle solution to a specific function is found by determining the effect carrier (material) and the geometry of the effects location. The physical effects are then applied through the working surfaces of the specific components (Pahl et al., 2015). In terms of knowledge-based engineering approaches principle solutions can be derived from various design catalogs. Knowledge databases (design catalogues) offer a preselection of the possible combinations of effect, the effect carrier and the concrete geometry shape (VDI, 2004; Koller and Kastrup, 1998). The decomposition of components and subassemblies by means of their working surface pairs has proved its worth in methodical analysis of technical systems since the 1980s in design methodology research and is known as the contact channel method (c&c-m). In combination with the known requirements to the product a statement about the behaviour of the entire system and individual components (e.g. deformation analysis, dynamic loading, jamming of components) can be made. In addition, suggestions for improvements can be proposed by identifying the cause-effect chain and its weak spots (Ersoy, 1975; Rodenacker and Claussen, 1973). Roth stated the theory of working surface pairs and the channel and support structures to be fundamentally the point of origin for initial shape design (Roth, 2000). Figure 2. Examples of external working surfaces according to Roth (Roth, 2000) ICED17 199 Matthiesen proved the contact and channel method to be particularly suitable for the determination of an intial component shape as well (Matthiesen, 2002). In order to ensure an efficient concept design, Lemburg enhanced those approaches by proposing a step-by-step shape determination (Lemburg, 2009). The c&c-m approach was intensively extended regarding the component analysis and optimization of already existing structures and partial solutions by Albers and Matthiesen (Albers and Matthiesen, 2002). They continued the described approaches and developed the "Contact and Channel Approach" (c&c-a), which can be used to analyse functional and creative